<PRE><B>Question 520647</B>
---------percent		----------------			quantity								
Acid type I	12	----------------			x	ml							
Acid type II	4	------	40	-	x	ml							
Mixture	10.00%	----------------	40										
													
12	x	+	4	(	40	-	x	)	=	10	*	40	
													
12x+160	-4x=400			
12 x-4x	=400-160			
8	x			=	240								
/	8												
	x			=	30		ml			12.00%		Acid type I	
					10		ml			4.00%		Acid type II	
													
</PRE>